Importance

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Abstract

An electromagnetic release drive, particularly suitable for a residual current circuit breaker, includes a plunger loaded by a spring in a release direction, a permanent magnet configuration, a coil and a yoke. The coil generates in the yoke a magnetic flux opposed to the permanent magnet configuration when the coil is driven or released such that the spring force overcomes the attraction force of the permanent magnet configuration. The permanent magnet configuration and the pole shoe conducting the magnetic flux to the plunger are associated with the yoke and the plunger such that, in a first position, the plunger is located in the active range of the permanent magnet configuration and of the pole shoe and, in a second position, is located at least partly in the active range of the pole shoe. Thus, in a first position, both the magnetic flux of the coil and that of the permanent magnet configuration, the latter at least partly, run through the plunger and, in the second position of the plunger, a closed magnetic circuit is formed by the yoke, the plunger, the pole shoe, and the permanent magnet configuration. The invention achieves two advantages. First, the working point of the permanent magnet configuration is maintained even in the release position, i.e., the second position. Second, the permanent magnet configuration can be magnetized with the coil.

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First Claim